A good method of discovery is to imagine certain members of a system removed and then see how what is left would behave: for example, where would we be if iron were absent from the world: this is an old example.

Prejudices are so to speak the mechanical instincts of men: through their prejudices they do without any effort many things they would find too difficult to think through to the point of resolving to do them.

If we make a couple of discoveries here and there we need not believe things will go on like this for ever. Just as we hit water when we dig in the earth, so we discover the incomprehensible sooner or later.

The highest point to which a weak but experienced mind can rise is detecting the weakness of better men.

A handful of soldiers is always better than a mouthful of arguments.

What a blessing it would be if we could open and shut our ears...as easily as we open and shut our eyes.

Cautiousness in judgment is nowadays to be recommended to each and every one: if we gained only one incontestable truth every ten years from each of our philosophical writers the harvest we reaped would be sufficient.